Good ole Fruitbat,
The citizen issue with ATCOs in the US is common knowledge, nothing new.
My question re green card was concerning a possible hiring of expats in the future, abandoning the citizenship requirement (otherwise FAA couldn't hire any expats, could they?).
Besides, ASA requires you to be a permanent resident. And as we know, getting permanent residency in Oz can take a wee while.
Furthermore, Skyguide is not hiring expats anymore UFN. And those expats who are working there now didn't have to apply for permanent residency, they were sponsored by the company.